Prof. Fessenden truly remarks there are two independent properties of matter—gravity and inertia—and these give two ways of defining force and energy.
It should always be remembered that electricity is something real, although not easily defined. And then, too, while it is not matter and not energy, yet under proper conditions (it having the power of doing work) it is convenient to speak of its performances as electric energy. The following questions and answers, although few in number, may present the subject with clearness.
Ques. What is energy?
Ans. Energy is the capacity for doing work.
Steam under pressure is an example, a spring bent ready to be released is another form, again, water stored in an elevated tank has capacity for doing work. These examples illustrate potential energy, as distinguished from kinetic energy. Potential energy may be defined as energy due to position, and kinetic energy, as energy due to momentum.
Ques. What is matter?
Ans. Matter is anything occupying space, and which prevents other matter occupying the same space at the same time.
Ques. What name is given the smallest quantity of matter which can exist?
Ans. The atom.
An atom means that which cannot be cut, scratched, or changed in form and that cannot be affected by heat or cold or any known force; although inconceivably small, atoms possess a definite size and mass.